Send a test of a broadcast to explicit recipients

Renders the broadcast and dispatches it to an explicit set of 1–10 recipients through the exact production plan + merge + SES path — the same from-address, template resolution, tracking, and unsubscribe footer the audience would receive — so you can eyeball the real email before sending to the audience.

A test send deliberately bypasses the audience and the consent filter: it goes to exactly the addresses you name, even if they are suppressed or opted out (it is a deliberate self-send). It never mutates the broadcast or its counts — test rows are excluded from GET /v1/broadcasts/{id}/results and from the broadcast's rollup. Allowed in any state; testing a draft is the common case.

sample_data overlays the broadcast's default_template_data for this render, so you can preview merge output for addresses that aren't contacts (for example, inject a rendered body_html). A recipient who is a contact still renders from their own attributes, which win over the sample.

Because it delivers real email, a test send is rate-limited per org (default 10/hour) on top of the general API limit — 429 rate_limited when the window is exhausted. An Idempotency-Key is accepted and ignored (test sends are intentionally repeatable). Returns 200 with one outcome per recipient, in request order.